We collect extensive data on worldwide trade by transportation mode and use this to provide detailed comparisons of the greenhouse gas emissions associated with output versus international transportation of traded goods. International transport is responsible for 33 percent of world-wide...

A large and growing share of international trade is carried on airplanes. Air cargo is many times more expensive than maritime transport but arrives in destination markets much faster. We model firms' choice between exporting goods using fast but expensive air cargo and slow but cheap ocean...

Purchasing goods from distant locations introduces a significant lag between when a product is shipped and when it arrives. This is problematic for firms facing volatile demand, who must place orders before knowing the resolution of demand uncertainty. We provide a model in which airplanes bring...

We examine a generalized version of Flam and Helpman’s (1987) model of vertical differentiation that maps cross-country differences in income distributions to variations in import variety and price distributions. The theoretical predictions are examined and confirmed using micro data on...